Filter blockages can be frustrating, time-consuming and have a detrimental impact on beer production. Dr Carolyn Heslop, technical support team leader at Parker Bioscience Filtration, puts a blockage issue under the microscope. 

If you are employing sterile filtration technology, do you find your beer line filters block regularly? Are you spending valuable time and money replacing filters, only to see them block again and stall your beer production process?

It may not be the fault of the filters you are using. The problem can often lie elsewhere.

And in one case recently addressed by Parker Bioscience Filtration’s Technical Support Group (TSG) the problem had its origins millions of years ago…

We were working with a European brewery which was using technology supplied by Parker Bioscience Filtration to perform sterile filtration of its beer products. 

The brewery was using 126 30-inch Parker Bioscience Filtration Bevpor BR filters to remove yeast and other spoilage organisms to ensure microbial stability of its products – and was also employing our Prepor NG filters upstream for pre-stabilization. These provide fully validated yeast removal and bacterial reduction for the brewery.

The filters had been successfully trialled and had been operating without any issues for a considerable period of time. However, the brewery then alerted us to the fact that the BEVPOR BR filters were starting to block much earlier than they would have normally expected.

We removed the affected Bevpor BR filters from the brewery and performed an in-depth blockage analysis. This process included dissecting the filters to examine the filter membrane and media in more detail. 

By using a scanning electron microscope, we could see that there was a high level of diatomaceous earth present on the membrane. Diatomaceous earth consists of fossilized remains of diatoms (algae found in oceans, waterways and soils), the hard shells of which are rich in silica. 

It was the high level of this substance which was causing the filters to block.

We discovered that due to increased demand for its beer products during the summer, the brewery had switched the line over to a beer line which was not being filtered by the Prepor NG products and instead was being passed straight through the Bevpor BR filters. This beer contained a high level of diatomaceous earth – but the process was not being protected from this substance by the Prepor NG filters.  

What is the lesson here?

Breweries need to be aware that process changes can have an impact on the effectiveness and lifespan of the filters that they are using – with the subsequent impact being increased downtime (while filters are removed and replaced) and increased operational costs. 

If you are planning to change your process fluid, before commencing sterile filtration of a beer product, you should consider the consequences of this for its current filtration system and the level of protection that should be provided by upstream filtration systems.

It could help you avoid a great deal of frustration in the long run…

Dr Carolyn Heslop is a BSc Hons qualified Chemist with a PhD in Analytical Chemistry. She has more than 18 years’ experience working in the food & beverage industry in technical and scientific roles.